Transgenic mice that have randomly inserted transgenes that contain a human IL-7 sequence are known in the art. However, most if not all of these transgenic mice are not optimal in one aspect or another. For example, most mice transgenic for human IL-7 exhibit abnormal levels and/or ratios of certain cells, including T cells, that are likely due to a dysregulation of immune cell development, e.g., T cell development.
There remains a need in the art for non-human animals that comprise human IL-7-encoding sequences, wherein the human IL-7 encoding sequences are at an endogenous non-human IL-7 locus, and for non-human animals that express human IL-7 under the control of endogenous non-human regulatory elements. There is a need in the art for non-human animals that express human IL-7 in a manner that is as physiologically relevant in the non-human animal as possible. There is a need in the art for non-human animals that express a human IL-7, wherein the non-human animals lack a significant abnormality in peripheral T cells, and/or in ratios of T cell subtypes.